/*
The MIT License (MIT)

Copyright (c) 2012-2016 Syoyo Fujita and many contributors.

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

//
// version 1.0.2 : Improve parsing speed by about a factor of 2 for large files(#105)
// version 1.0.1 : Fixes a shape is lost if obj ends with a 'usemtl'(#104)
// version 1.0.0 : Change data structure. Change license from BSD to MIT.
//

//
// Use this in *one* .cc
//   #define TINYOBJLOADER_IMPLEMENTATION
//   #include "tiny_obj_loader.h"
//

#ifndef TINY_OBJ_LOADER_H_
#define TINY_OBJ_LOADER_H_

#include <map>
#include <string>
#include <vector>

namespace tinyobj {

	typedef struct {
		std::string name;

		float ambient[3];
		float diffuse[3];
		float specular[3];
		float transmittance[3];
		float emission[3];
		float shininess;
		float ior;       // index of refraction
		float dissolve;  // 1 == opaque; 0 == fully transparent
		int illum;

		int dummy;  // Suppress padding warning.

		std::string ambient_texname;             // map_Ka
		std::string diffuse_texname;             // map_Kd
		std::string specular_texname;            // map_Ks
		std::string specular_highlight_texname;  // map_Ns
		std::string bump_texname;                // map_bump, bump
		std::string displacement_texname;        // disp
		std::string alpha_texname;               // map_d

												 // PBR extension
		float roughness;                // [0, 1] default 0
		float metallic;                 // [0, 1] default 0
		float sheen;                    // [0, 1] default 0
		float clearcoat_thickness;      // [0, 1] default 0
		float clearcoat_roughness;      // [0, 1] default 0
		float anisotropy;               // aniso. [0, 1] default 0
		float anisotropy_rotation;      // anisor. [0, 1] default 0
		float pad0;
		std::string roughness_texname;  // map_Pr
		std::string metallic_texname;   // map_Pm
		std::string sheen_texname;      // map_Ps
		std::string emissive_texname;   // map_Ke
		std::string normal_texname;     // norm. For normal mapping.

		std::map<std::string, std::string> unknown_parameter;
	} material_t;

	typedef struct {
		std::string name;

		std::vector<int> intValues;
		std::vector<float> floatValues;
		std::vector<std::string> stringValues;
	} tag_t;

	// Index struct to support different indices for vtx/normal/texcoord.
	// -1 means not used.
	typedef struct {
		int vertex_index;
		int normal_index;
		int texcoord_index;
	} index_t;

	typedef struct {
		std::vector<index_t> indices;
		std::vector<unsigned char> num_face_vertices;  // The number of vertices per
													   // face. 3 = polygon, 4 = quad,
													   // ... Up to 255.
		std::vector<int> material_ids;                 // per-face material ID
		std::vector<tag_t> tags;                       // SubD tag
	} mesh_t;

	typedef struct {
		std::string name;
		mesh_t mesh;
	} shape_t;

	// Vertex attributes
	typedef struct {
		std::vector<float> vertices;   // 'v'
		std::vector<float> normals;    // 'vn'
		std::vector<float> texcoords;  // 'vt'
	} attrib_t;

	typedef struct callback_t_ {
		// W is optional and set to 1 if there is no `w` item in `v` line
		void(*vertex_cb)(void *user_data, float x, float y, float z, float w);
		void(*normal_cb)(void *user_data, float x, float y, float z);

		// y and z are optional and set to 0 if there is no `y` and/or `z` item(s) in
		// `vt` line.
		void(*texcoord_cb)(void *user_data, float x, float y, float z);

		// called per 'f' line. num_indices is the number of face indices(e.g. 3 for
		// triangle, 4 for quad)
		// 0 will be passed for undefined index in index_t members.
		void(*index_cb)(void *user_data, index_t *indices, int num_indices);
		// `name` material name, `material_id` = the array index of material_t[]. -1
		// if
		// a material not found in .mtl
		void(*usemtl_cb)(void *user_data, const char *name, int material_id);
		// `materials` = parsed material data.
		void(*mtllib_cb)(void *user_data, const material_t *materials,
			int num_materials);
		// There may be multiple group names
		void(*group_cb)(void *user_data, const char **names, int num_names);
		void(*object_cb)(void *user_data, const char *name);

		callback_t_()
			: vertex_cb(NULL),
			normal_cb(NULL),
			texcoord_cb(NULL),
			index_cb(NULL),
			usemtl_cb(NULL),
			mtllib_cb(NULL),
			group_cb(NULL),
			object_cb(NULL) {}
	} callback_t;

	class MaterialReader {
	public:
		MaterialReader() {}
		virtual ~MaterialReader();

		virtual bool operator()(const std::string &matId,
			std::vector<material_t> *materials,
			std::map<std::string, int> *matMap,
			std::string *err) = 0;
	};

	class MaterialFileReader : public MaterialReader {
	public:
		explicit MaterialFileReader(const std::string &mtl_basepath)
			: m_mtlBasePath(mtl_basepath) {}
		virtual ~MaterialFileReader() {}
		virtual bool operator()(const std::string &matId,
			std::vector<material_t> *materials,
			std::map<std::string, int> *matMap, std::string *err);

	private:
		std::string m_mtlBasePath;
	};

	class MaterialStreamReader : public MaterialReader {
	public:
		explicit MaterialStreamReader(std::istream &inStream)
			: m_inStream(inStream) {}
		virtual ~MaterialStreamReader() {}
		virtual bool operator()(const std::string &matId,
			std::vector<material_t> *materials,
			std::map<std::string, int> *matMap, std::string *err);

	private:
		std::istream &m_inStream;
	};

	/// Loads .obj from a file.
	/// 'attrib', 'shapes' and 'materials' will be filled with parsed shape data
	/// 'shapes' will be filled with parsed shape data
	/// Returns true when loading .obj become success.
	/// Returns warning and error message into `err`
	/// 'mtl_basepath' is optional, and used for base path for .mtl file.
	/// 'triangulate' is optional, and used whether triangulate polygon face in .obj
	/// or not.
	bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
		std::vector<material_t> *materials, std::string *err,
		const char *filename, const char *mtl_basepath = NULL,
		bool triangulate = true);

	/// Loads .obj from a file with custom user callback.
	/// .mtl is loaded as usual and parsed material_t data will be passed to
	/// `callback.mtllib_cb`.
	/// Returns true when loading .obj/.mtl become success.
	/// Returns warning and error message into `err`
	/// See `examples/callback_api/` for how to use this function.
	bool LoadObjWithCallback(std::istream &inStream, const callback_t &callback,
		void *user_data = NULL,
		MaterialReader *readMatFn = NULL,
		std::string *err = NULL);

	/// Loads object from a std::istream, uses GetMtlIStreamFn to retrieve
	/// std::istream for materials.
	/// Returns true when loading .obj become success.
	/// Returns warning and error message into `err`
	bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
		std::vector<material_t> *materials, std::string *err,
		std::istream *inStream, MaterialReader *readMatFn = NULL,
		bool triangulate = true);

	/// Loads materials into std::map
	void LoadMtl(std::map<std::string, int> *material_map,
		std::vector<material_t> *materials, std::istream *inStream);

}  // namespace tinyobj

#ifdef TINYOBJLOADER_IMPLEMENTATION
#include <cassert>
#include <cctype>
#include <cmath>
#include <cstddef>
#include <cstdlib>
#include <cstring>
#include <utility>

#include <fstream>
#include <sstream>

namespace tinyobj {

	MaterialReader::~MaterialReader() {}

#define TINYOBJ_SSCANF_BUFFER_SIZE (4096)

	struct vertex_index {
		int v_idx, vt_idx, vn_idx;
		vertex_index() : v_idx(-1), vt_idx(-1), vn_idx(-1) {}
		explicit vertex_index(int idx) : v_idx(idx), vt_idx(idx), vn_idx(idx) {}
		vertex_index(int vidx, int vtidx, int vnidx)
			: v_idx(vidx), vt_idx(vtidx), vn_idx(vnidx) {}
	};

	struct tag_sizes {
		tag_sizes() : num_ints(0), num_floats(0), num_strings(0) {}
		int num_ints;
		int num_floats;
		int num_strings;
	};

	struct obj_shape {
		std::vector<float> v;
		std::vector<float> vn;
		std::vector<float> vt;
	};

	static std::istream &safeGetline(std::istream &is, std::string &t) {
		t.clear();

		// The characters in the stream are read one-by-one using a std::streambuf.
		// That is faster than reading them one-by-one using the std::istream.
		// Code that uses streambuf this way must be guarded by a sentry object.
		// The sentry object performs various tasks,
		// such as thread synchronization and updating the stream state.

		std::istream::sentry se(is, true);
		std::streambuf *sb = is.rdbuf();

		for (;;) {
			int c = sb->sbumpc();
			switch (c) {
			case '\n':
				return is;
			case '\r':
				if (sb->sgetc() == '\n') sb->sbumpc();
				return is;
			case EOF:
				// Also handle the case when the last line has no line ending
				if (t.empty()) is.setstate(std::ios::eofbit);
				return is;
			default:
				t += static_cast<char>(c);
			}
		}
	}

#define IS_SPACE(x) (((x) == ' ') || ((x) == '\t'))
#define IS_DIGIT(x) \
  (static_cast<unsigned int>((x) - '0') < static_cast<unsigned int>(10))
#define IS_NEW_LINE(x) (((x) == '\r') || ((x) == '\n') || ((x) == '\0'))

	// Make index zero-base, and also support relative index.
	static inline int fixIndex(int idx, int n) {
		if (idx > 0) return idx - 1;
		if (idx == 0) return 0;
		return n + idx;  // negative value = relative
	}

	static inline std::string parseString(const char **token) {
		std::string s;
		(*token) += strspn((*token), " \t");
		size_t e = strcspn((*token), " \t\r");
		s = std::string((*token), &(*token)[e]);
		(*token) += e;
		return s;
	}

	static inline int parseInt(const char **token) {
		(*token) += strspn((*token), " \t");
		int i = atoi((*token));
		(*token) += strcspn((*token), " \t\r");
		return i;
	}

	// Tries to parse a floating point number located at s.
	//
	// s_end should be a location in the string where reading should absolutely
	// stop. For example at the end of the string, to prevent buffer overflows.
	//
	// Parses the following EBNF grammar:
	//   sign    = "+" | "-" ;
	//   END     = ? anything not in digit ?
	//   digit   = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" ;
	//   integer = [sign] , digit , {digit} ;
	//   decimal = integer , ["." , integer] ;
	//   float   = ( decimal , END ) | ( decimal , ("E" | "e") , integer , END ) ;
	//
	//  Valid strings are for example:
	//   -0  +3.1417e+2  -0.0E-3  1.0324  -1.41   11e2
	//
	// If the parsing is a success, result is set to the parsed value and true
	// is returned.
	//
	// The function is greedy and will parse until any of the following happens:
	//  - a non-conforming character is encountered.
	//  - s_end is reached.
	//
	// The following situations triggers a failure:
	//  - s >= s_end.
	//  - parse failure.
	//
	static bool tryParseDouble(const char *s, const char *s_end, double *result) {
		if (s >= s_end) {
			return false;
		}

		double mantissa = 0.0;
		// This exponent is base 2 rather than 10.
		// However the exponent we parse is supposed to be one of ten,
		// thus we must take care to convert the exponent/and or the
		// mantissa to a * 2^E, where a is the mantissa and E is the
		// exponent.
		// To get the final double we will use ldexp, it requires the
		// exponent to be in base 2.
		int exponent = 0;

		// NOTE: THESE MUST BE DECLARED HERE SINCE WE ARE NOT ALLOWED
		// TO JUMP OVER DEFINITIONS.
		char sign = '+';
		char exp_sign = '+';
		char const *curr = s;

		// How many characters were read in a loop.
		int read = 0;
		// Tells whether a loop terminated due to reaching s_end.
		bool end_not_reached = false;

		/*
		BEGIN PARSING.
		*/

		// Find out what sign we've got.
		if (*curr == '+' || *curr == '-') {
			sign = *curr;
			curr++;
		}
		else if (IS_DIGIT(*curr)) { /* Pass through. */
		}
		else {
			goto fail;
		}

		// Read the integer part.
		end_not_reached = (curr != s_end);
		while (end_not_reached && IS_DIGIT(*curr)) {
			mantissa *= 10;
			mantissa += static_cast<int>(*curr - 0x30);
			curr++;
			read++;
			end_not_reached = (curr != s_end);
		}

		// We must make sure we actually got something.
		if (read == 0) goto fail;
		// We allow numbers of form "#", "###" etc.
		if (!end_not_reached) goto assemble;

		// Read the decimal part.
		if (*curr == '.') {
			curr++;
			read = 1;
			end_not_reached = (curr != s_end);
			while (end_not_reached && IS_DIGIT(*curr)) {
				static const double pow_lut[] = {
					1.0,
					0.1,
					0.01,
					0.001,
					0.0001,
					0.00001,
					0.000001,
					0.0000001,
				};
				const int lut_entries = sizeof pow_lut / sizeof pow_lut[0];

				// NOTE: Don't use powf here, it will absolutely murder precision.
				mantissa += static_cast<int>(*curr - 0x30) *
					(read < lut_entries ? pow_lut[read] : pow(10.0, -read));
				read++;
				curr++;
				end_not_reached = (curr != s_end);
			}
		}
		else if (*curr == 'e' || *curr == 'E') {
		}
		else {
			goto assemble;
		}

		if (!end_not_reached) goto assemble;

		// Read the exponent part.
		if (*curr == 'e' || *curr == 'E') {
			curr++;
			// Figure out if a sign is present and if it is.
			end_not_reached = (curr != s_end);
			if (end_not_reached && (*curr == '+' || *curr == '-')) {
				exp_sign = *curr;
				curr++;
			}
			else if (IS_DIGIT(*curr)) { /* Pass through. */
			}
			else {
				// Empty E is not allowed.
				goto fail;
			}

			read = 0;
			end_not_reached = (curr != s_end);
			while (end_not_reached && IS_DIGIT(*curr)) {
				exponent *= 10;
				exponent += static_cast<int>(*curr - 0x30);
				curr++;
				read++;
				end_not_reached = (curr != s_end);
			}
			exponent *= (exp_sign == '+' ? 1 : -1);
			if (read == 0) goto fail;
		}

	assemble:
		*result = (sign == '+' ? 1 : -1) *
			(exponent ? ldexp(mantissa * pow(5.0, exponent), exponent) : mantissa);
		return true;
	fail:
		return false;
	}

	static inline float parseFloat(const char **token, double default_value = 0.0) {
		(*token) += strspn((*token), " \t");
		const char *end = (*token) + strcspn((*token), " \t\r");
		double val = default_value;
		tryParseDouble((*token), end, &val);
		float f = static_cast<float>(val);
		(*token) = end;
		return f;
	}

	static inline void parseFloat2(float *x, float *y, const char **token) {
		(*x) = parseFloat(token);
		(*y) = parseFloat(token);
	}

	static inline void parseFloat3(float *x, float *y, float *z,
		const char **token) {
		(*x) = parseFloat(token);
		(*y) = parseFloat(token);
		(*z) = parseFloat(token);
	}

	static inline void parseV(float *x, float *y, float *z, float *w,
		const char **token) {
		(*x) = parseFloat(token);
		(*y) = parseFloat(token);
		(*z) = parseFloat(token);
		(*w) = parseFloat(token, 1.0);
	}

	static tag_sizes parseTagTriple(const char **token) {
		tag_sizes ts;

		ts.num_ints = atoi((*token));
		(*token) += strcspn((*token), "/ \t\r");
		if ((*token)[0] != '/') {
			return ts;
		}
		(*token)++;

		ts.num_floats = atoi((*token));
		(*token) += strcspn((*token), "/ \t\r");
		if ((*token)[0] != '/') {
			return ts;
		}
		(*token)++;

		ts.num_strings = atoi((*token));
		(*token) += strcspn((*token), "/ \t\r") + 1;

		return ts;
	}

	// Parse triples with index offsets: i, i/j/k, i//k, i/j
	static vertex_index parseTriple(const char **token, int vsize, int vnsize,
		int vtsize) {
		vertex_index vi(-1);

		vi.v_idx = fixIndex(atoi((*token)), vsize);
		(*token) += strcspn((*token), "/ \t\r");
		if ((*token)[0] != '/') {
			return vi;
		}
		(*token)++;

		// i//k
		if ((*token)[0] == '/') {
			(*token)++;
			vi.vn_idx = fixIndex(atoi((*token)), vnsize);
			(*token) += strcspn((*token), "/ \t\r");
			return vi;
		}

		// i/j/k or i/j
		vi.vt_idx = fixIndex(atoi((*token)), vtsize);
		(*token) += strcspn((*token), "/ \t\r");
		if ((*token)[0] != '/') {
			return vi;
		}

		// i/j/k
		(*token)++;  // skip '/'
		vi.vn_idx = fixIndex(atoi((*token)), vnsize);
		(*token) += strcspn((*token), "/ \t\r");
		return vi;
	}

	// Parse raw triples: i, i/j/k, i//k, i/j
	static vertex_index parseRawTriple(const char **token) {
		vertex_index vi(static_cast<int>(0));  // 0 is an invalid index in OBJ

		vi.v_idx = atoi((*token));
		(*token) += strcspn((*token), "/ \t\r");
		if ((*token)[0] != '/') {
			return vi;
		}
		(*token)++;

		// i//k
		if ((*token)[0] == '/') {
			(*token)++;
			vi.vn_idx = atoi((*token));
			(*token) += strcspn((*token), "/ \t\r");
			return vi;
		}

		// i/j/k or i/j
		vi.vt_idx = atoi((*token));
		(*token) += strcspn((*token), "/ \t\r");
		if ((*token)[0] != '/') {
			return vi;
		}

		// i/j/k
		(*token)++;  // skip '/'
		vi.vn_idx = atoi((*token));
		(*token) += strcspn((*token), "/ \t\r");
		return vi;
	}

	static void InitMaterial(material_t *material) {
		material->name = "";
		material->ambient_texname = "";
		material->diffuse_texname = "";
		material->specular_texname = "";
		material->specular_highlight_texname = "";
		material->bump_texname = "";
		material->displacement_texname = "";
		material->alpha_texname = "";
		for (int i = 0; i < 3; i++) {
			material->ambient[i] = 0.f;
			material->diffuse[i] = 0.f;
			material->specular[i] = 0.f;
			material->transmittance[i] = 0.f;
			material->emission[i] = 0.f;
		}
		material->illum = 0;
		material->dissolve = 1.f;
		material->shininess = 1.f;
		material->ior = 1.f;

		material->roughness = 0.f;
		material->metallic = 0.f;
		material->sheen = 0.f;
		material->clearcoat_thickness = 0.f;
		material->clearcoat_roughness = 0.f;
		material->anisotropy_rotation = 0.f;
		material->anisotropy = 0.f;
		material->roughness_texname = "";
		material->metallic_texname = "";
		material->sheen_texname = "";
		material->emissive_texname = "";
		material->normal_texname = "";

		material->unknown_parameter.clear();
	}

	static bool exportFaceGroupToShape(
		shape_t *shape, const std::vector<std::vector<vertex_index> > &faceGroup,
		const std::vector<tag_t> &tags, const int material_id,
		const std::string &name, bool triangulate) {
		if (faceGroup.empty()) {
			return false;
		}

		// Flatten vertices and indices
		for (size_t i = 0; i < faceGroup.size(); i++) {
			const std::vector<vertex_index> &face = faceGroup[i];

			vertex_index i0 = face[0];
			vertex_index i1(-1);
			vertex_index i2 = face[1];

			size_t npolys = face.size();

			if (triangulate) {
				// Polygon -> triangle fan conversion
				for (size_t k = 2; k < npolys; k++) {
					i1 = i2;
					i2 = face[k];

					index_t idx0, idx1, idx2;
					idx0.vertex_index = i0.v_idx;
					idx0.normal_index = i0.vn_idx;
					idx0.texcoord_index = i0.vt_idx;
					idx1.vertex_index = i1.v_idx;
					idx1.normal_index = i1.vn_idx;
					idx1.texcoord_index = i1.vt_idx;
					idx2.vertex_index = i2.v_idx;
					idx2.normal_index = i2.vn_idx;
					idx2.texcoord_index = i2.vt_idx;

					shape->mesh.indices.push_back(idx0);
					shape->mesh.indices.push_back(idx1);
					shape->mesh.indices.push_back(idx2);

					shape->mesh.num_face_vertices.push_back(3);
					shape->mesh.material_ids.push_back(material_id);
				}
			}
			else {
				for (size_t k = 0; k < npolys; k++) {
					index_t idx;
					idx.vertex_index = face[k].v_idx;
					idx.normal_index = face[k].vn_idx;
					idx.texcoord_index = face[k].vt_idx;
					shape->mesh.indices.push_back(idx);
				}

				shape->mesh.num_face_vertices.push_back(
					static_cast<unsigned char>(npolys));
				shape->mesh.material_ids.push_back(material_id);  // per face
			}
		}

		shape->name = name;
		shape->mesh.tags = tags;

		return true;
	}

	void LoadMtl(std::map<std::string, int> *material_map,
		std::vector<material_t> *materials, std::istream *inStream) {
		// Create a default material anyway.
		material_t material;
		InitMaterial(&material);

		std::string linebuf;
		while (inStream->peek() != -1) {
			safeGetline(*inStream, linebuf);

			// Trim trailing whitespace.
			if (linebuf.size() > 0) {
				linebuf = linebuf.substr(0, linebuf.find_last_not_of(" \t") + 1);
			}

			// Trim newline '\r\n' or '\n'
			if (linebuf.size() > 0) {
				if (linebuf[linebuf.size() - 1] == '\n')
					linebuf.erase(linebuf.size() - 1);
			}
			if (linebuf.size() > 0) {
				if (linebuf[linebuf.size() - 1] == '\r')
					linebuf.erase(linebuf.size() - 1);
			}

			// Skip if empty line.
			if (linebuf.empty()) {
				continue;
			}

			// Skip leading space.
			const char *token = linebuf.c_str();
			token += strspn(token, " \t");

			assert(token);
			if (token[0] == '\0') continue;  // empty line

			if (token[0] == '#') continue;  // comment line

											// new mtl
			if ((0 == strncmp(token, "newmtl", 6)) && IS_SPACE((token[6]))) {
				// flush previous material.
				if (!material.name.empty()) {
					material_map->insert(std::pair<std::string, int>(
						material.name, static_cast<int>(materials->size())));
					materials->push_back(material);
				}

				// initial temporary material
				InitMaterial(&material);

				// set new mtl name
				char namebuf[TINYOBJ_SSCANF_BUFFER_SIZE];
				token += 7;
#ifdef _MSC_VER
				sscanf_s(token, "%s", namebuf, (unsigned)_countof(namebuf));
#else
				sscanf(token, "%s", namebuf);
#endif
				material.name = namebuf;
				continue;
			}

			// ambient
			if (token[0] == 'K' && token[1] == 'a' && IS_SPACE((token[2]))) {
				token += 2;
				float r, g, b;
				parseFloat3(&r, &g, &b, &token);
				material.ambient[0] = r;
				material.ambient[1] = g;
				material.ambient[2] = b;
				continue;
			}

			// diffuse
			if (token[0] == 'K' && token[1] == 'd' && IS_SPACE((token[2]))) {
				token += 2;
				float r, g, b;
				parseFloat3(&r, &g, &b, &token);
				material.diffuse[0] = r;
				material.diffuse[1] = g;
				material.diffuse[2] = b;
				continue;
			}

			// specular
			if (token[0] == 'K' && token[1] == 's' && IS_SPACE((token[2]))) {
				token += 2;
				float r, g, b;
				parseFloat3(&r, &g, &b, &token);
				material.specular[0] = r;
				material.specular[1] = g;
				material.specular[2] = b;
				continue;
			}

			// transmittance
			if ((token[0] == 'K' && token[1] == 't' && IS_SPACE((token[2]))) ||
				(token[0] == 'T' && token[1] == 'f' && IS_SPACE((token[2])))) {
				token += 2;
				float r, g, b;
				parseFloat3(&r, &g, &b, &token);
				material.transmittance[0] = r;
				material.transmittance[1] = g;
				material.transmittance[2] = b;
				continue;
			}

			// ior(index of refraction)
			if (token[0] == 'N' && token[1] == 'i' && IS_SPACE((token[2]))) {
				token += 2;
				material.ior = parseFloat(&token);
				continue;
			}

			// emission
			if (token[0] == 'K' && token[1] == 'e' && IS_SPACE(token[2])) {
				token += 2;
				float r, g, b;
				parseFloat3(&r, &g, &b, &token);
				material.emission[0] = r;
				material.emission[1] = g;
				material.emission[2] = b;
				continue;
			}

			// shininess
			if (token[0] == 'N' && token[1] == 's' && IS_SPACE(token[2])) {
				token += 2;
				material.shininess = parseFloat(&token);
				continue;
			}

			// illum model
			if (0 == strncmp(token, "illum", 5) && IS_SPACE(token[5])) {
				token += 6;
				material.illum = parseInt(&token);
				continue;
			}

			// dissolve
			if ((token[0] == 'd' && IS_SPACE(token[1]))) {
				token += 1;
				material.dissolve = parseFloat(&token);
				continue;
			}
			if (token[0] == 'T' && token[1] == 'r' && IS_SPACE(token[2])) {
				token += 2;
				// Invert value of Tr(assume Tr is in range [0, 1])
				material.dissolve = 1.0f - parseFloat(&token);
				continue;
			}

			// PBR: roughness
			if (token[0] == 'P' && token[1] == 'r' && IS_SPACE(token[2])) {
				token += 2;
				material.roughness = parseFloat(&token);
				continue;
			}

			// PBR: metallic
			if (token[0] == 'P' && token[1] == 'm' && IS_SPACE(token[2])) {
				token += 2;
				material.metallic = parseFloat(&token);
				continue;
			}

			// PBR: sheen
			if (token[0] == 'P' && token[1] == 's' && IS_SPACE(token[2])) {
				token += 2;
				material.sheen = parseFloat(&token);
				continue;
			}

			// PBR: clearcoat thickness
			if (token[0] == 'P' && token[1] == 'c' && IS_SPACE(token[2])) {
				token += 2;
				material.clearcoat_thickness = parseFloat(&token);
				continue;
			}

			// PBR: clearcoat roughness
			if ((0 == strncmp(token, "Pcr", 3)) && IS_SPACE(token[3])) {
				token += 4;
				material.clearcoat_roughness = parseFloat(&token);
				continue;
			}

			// PBR: anisotropy
			if ((0 == strncmp(token, "aniso", 5)) && IS_SPACE(token[5])) {
				token += 6;
				material.anisotropy = parseFloat(&token);
				continue;
			}

			// PBR: anisotropy rotation
			if ((0 == strncmp(token, "anisor", 6)) && IS_SPACE(token[6])) {
				token += 7;
				material.anisotropy_rotation = parseFloat(&token);
				continue;
			}

			// ambient texture
			if ((0 == strncmp(token, "map_Ka", 6)) && IS_SPACE(token[6])) {
				token += 7;
				material.ambient_texname = token;
				continue;
			}

			// diffuse texture
			if ((0 == strncmp(token, "map_Kd", 6)) && IS_SPACE(token[6])) {
				token += 7;
				material.diffuse_texname = token;
				continue;
			}

			// specular texture
			if ((0 == strncmp(token, "map_Ks", 6)) && IS_SPACE(token[6])) {
				token += 7;
				material.specular_texname = token;
				continue;
			}

			// specular highlight texture
			if ((0 == strncmp(token, "map_Ns", 6)) && IS_SPACE(token[6])) {
				token += 7;
				material.specular_highlight_texname = token;
				continue;
			}

			// bump texture
			if ((0 == strncmp(token, "map_bump", 8)) && IS_SPACE(token[8])) {
				token += 9;
				material.bump_texname = token;
				continue;
			}

			// alpha texture
			if ((0 == strncmp(token, "map_d", 5)) && IS_SPACE(token[5])) {
				token += 6;
				material.alpha_texname = token;
				continue;
			}

			// bump texture
			if ((0 == strncmp(token, "bump", 4)) && IS_SPACE(token[4])) {
				token += 5;
				material.bump_texname = token;
				continue;
			}

			// displacement texture
			if ((0 == strncmp(token, "disp", 4)) && IS_SPACE(token[4])) {
				token += 5;
				material.displacement_texname = token;
				continue;
			}

			// PBR: roughness texture
			if ((0 == strncmp(token, "map_Pr", 6)) && IS_SPACE(token[6])) {
				token += 7;
				material.roughness_texname = token;
				continue;
			}

			// PBR: metallic texture
			if ((0 == strncmp(token, "map_Pm", 6)) && IS_SPACE(token[6])) {
				token += 7;
				material.metallic_texname = token;
				continue;
			}

			// PBR: sheen texture
			if ((0 == strncmp(token, "map_Ps", 6)) && IS_SPACE(token[6])) {
				token += 7;
				material.sheen_texname = token;
				continue;
			}

			// PBR: emissive texture
			if ((0 == strncmp(token, "map_Ke", 6)) && IS_SPACE(token[6])) {
				token += 7;
				material.emissive_texname = token;
				continue;
			}

			// PBR: normal map texture
			if ((0 == strncmp(token, "norm", 4)) && IS_SPACE(token[4])) {
				token += 5;
				material.normal_texname = token;
				continue;
			}

			// unknown parameter
			const char *_space = strchr(token, ' ');
			if (!_space) {
				_space = strchr(token, '\t');
			}
			if (_space) {
				std::ptrdiff_t len = _space - token;
				std::string key(token, static_cast<size_t>(len));
				std::string value = _space + 1;
				material.unknown_parameter.insert(
					std::pair<std::string, std::string>(key, value));
			}
		}
		// flush last material.
		material_map->insert(std::pair<std::string, int>(
			material.name, static_cast<int>(materials->size())));
		materials->push_back(material);
	}

	bool MaterialFileReader::operator()(const std::string &matId,
		std::vector<material_t> *materials,
		std::map<std::string, int> *matMap,
		std::string *err) {
		std::string filepath;

		if (!m_mtlBasePath.empty()) {
			filepath = std::string(m_mtlBasePath) + matId;
		}
		else {
			filepath = matId;
		}

		std::ifstream matIStream(filepath.c_str());
		LoadMtl(matMap, materials, &matIStream);
		if (!matIStream) {
			std::stringstream ss;
			ss << "WARN: Material file [ " << filepath
				<< " ] not found. Created a default material.";
			if (err) {
				(*err) += ss.str();
			}
		}
		return true;
	}

	bool MaterialStreamReader::operator()(const std::string &matId,
		std::vector<material_t> *materials,
		std::map<std::string, int> *matMap,
		std::string *err) {
		(void)matId;
		LoadMtl(matMap, materials, &m_inStream);
		if (!m_inStream) {
			std::stringstream ss;
			ss << "WARN: Material stream in error state."
				<< " Created a default material.";
			if (err) {
				(*err) += ss.str();
			}
		}
		return true;
	}

	bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
		std::vector<material_t> *materials, std::string *err,
		const char *filename, const char *mtl_basepath,
		bool trianglulate) {
		attrib->vertices.clear();
		attrib->normals.clear();
		attrib->texcoords.clear();
		shapes->clear();

		std::stringstream errss;

		std::ifstream ifs(filename);
		if (!ifs) {
			errss << "Cannot open file [" << filename << "]" << std::endl;
			if (err) {
				(*err) = errss.str();
			}
			return false;
		}

		std::string basePath;
		if (mtl_basepath) {
			basePath = mtl_basepath;
		}
		MaterialFileReader matFileReader(basePath);

		return LoadObj(attrib, shapes, materials, err, &ifs, &matFileReader,
			trianglulate);
	}

	bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
		std::vector<material_t> *materials, std::string *err,
		std::istream *inStream,
		MaterialReader *readMatFn /*= NULL*/,
		bool triangulate) {
		std::stringstream errss;

		std::vector<float> v;
		std::vector<float> vn;
		std::vector<float> vt;
		std::vector<tag_t> tags;
		std::vector<std::vector<vertex_index> > faceGroup;
		std::string name;

		// material
		std::map<std::string, int> material_map;
		int material = -1;

		shape_t shape;

		std::string linebuf;
		while (inStream->peek() != -1) {
			safeGetline(*inStream, linebuf);

			// Trim newline '\r\n' or '\n'
			if (linebuf.size() > 0) {
				if (linebuf[linebuf.size() - 1] == '\n')
					linebuf.erase(linebuf.size() - 1);
			}
			if (linebuf.size() > 0) {
				if (linebuf[linebuf.size() - 1] == '\r')
					linebuf.erase(linebuf.size() - 1);
			}

			// Skip if empty line.
			if (linebuf.empty()) {
				continue;
			}

			// Skip leading space.
			const char *token = linebuf.c_str();
			token += strspn(token, " \t");

			assert(token);
			if (token[0] == '\0') continue;  // empty line

			if (token[0] == '#') continue;  // comment line

											// vertex
			if (token[0] == 'v' && IS_SPACE((token[1]))) {
				token += 2;
				float x, y, z;
				parseFloat3(&x, &y, &z, &token);
				v.push_back(x);
				v.push_back(y);
				v.push_back(z);
				continue;
			}

			// normal
			if (token[0] == 'v' && token[1] == 'n' && IS_SPACE((token[2]))) {
				token += 3;
				float x, y, z;
				parseFloat3(&x, &y, &z, &token);
				vn.push_back(x);
				vn.push_back(y);
				vn.push_back(z);
				continue;
			}

			// texcoord
			if (token[0] == 'v' && token[1] == 't' && IS_SPACE((token[2]))) {
				token += 3;
				float x, y;
				parseFloat2(&x, &y, &token);
				vt.push_back(x);
				vt.push_back(y);
				continue;
			}

			// face
			if (token[0] == 'f' && IS_SPACE((token[1]))) {
				token += 2;
				token += strspn(token, " \t");

				std::vector<vertex_index> face;
				face.reserve(3);

				while (!IS_NEW_LINE(token[0])) {
					vertex_index vi = parseTriple(&token, static_cast<int>(v.size() / 3),
						static_cast<int>(vn.size() / 3),
						static_cast<int>(vt.size() / 2));
					face.push_back(vi);
					size_t n = strspn(token, " \t\r");
					token += n;
				}

				// replace with emplace_back + std::move on C++11
				faceGroup.push_back(std::vector<vertex_index>());
				faceGroup[faceGroup.size() - 1].swap(face);

				continue;
			}

			// use mtl
			if ((0 == strncmp(token, "usemtl", 6)) && IS_SPACE((token[6]))) {
				char namebuf[TINYOBJ_SSCANF_BUFFER_SIZE];
				token += 7;
#ifdef _MSC_VER
				sscanf_s(token, "%s", namebuf, (unsigned)_countof(namebuf));
#else
				sscanf(token, "%s", namebuf);
#endif

				int newMaterialId = -1;
				if (material_map.find(namebuf) != material_map.end()) {
					newMaterialId = material_map[namebuf];
				}
				else {
					// { error!! material not found }
				}

				if (newMaterialId != material) {
					// Create per-face material. Thus we don't add `shape` to `shapes` at
					// this time.
					// just clear `faceGroup` after `exportFaceGroupToShape()` call.
					exportFaceGroupToShape(&shape, faceGroup, tags, material, name,
						triangulate);
					faceGroup.clear();
					material = newMaterialId;
				}

				continue;
			}

			// load mtl
			if ((0 == strncmp(token, "mtllib", 6)) && IS_SPACE((token[6]))) {
				if (readMatFn) {
					char namebuf[TINYOBJ_SSCANF_BUFFER_SIZE];
					token += 7;
#ifdef _MSC_VER
					sscanf_s(token, "%s", namebuf, (unsigned)_countof(namebuf));
#else
					sscanf(token, "%s", namebuf);
#endif

					std::string err_mtl;
					bool ok = (*readMatFn)(namebuf, materials, &material_map, &err_mtl);
					if (err) {
						(*err) += err_mtl;
					}

					if (!ok) {
						faceGroup.clear();  // for safety
						return false;
					}
				}

				continue;
			}

			// group name
			if (token[0] == 'g' && IS_SPACE((token[1]))) {
				// flush previous face group.
				bool ret = exportFaceGroupToShape(&shape, faceGroup, tags, material, name,
					triangulate);
				if (ret) {
					shapes->push_back(shape);
				}

				shape = shape_t();

				// material = -1;
				faceGroup.clear();

				std::vector<std::string> names;
				names.reserve(2);

				while (!IS_NEW_LINE(token[0])) {
					std::string str = parseString(&token);
					names.push_back(str);
					token += strspn(token, " \t\r");  // skip tag
				}

				assert(names.size() > 0);

				// names[0] must be 'g', so skip the 0th element.
				if (names.size() > 1) {
					name = names[1];
				}
				else {
					name = "";
				}

				continue;
			}

			// object name
			if (token[0] == 'o' && IS_SPACE((token[1]))) {
				// flush previous face group.
				bool ret = exportFaceGroupToShape(&shape, faceGroup, tags, material, name,
					triangulate);
				if (ret) {
					shapes->push_back(shape);
				}

				// material = -1;
				faceGroup.clear();
				shape = shape_t();

				char namebuf[TINYOBJ_SSCANF_BUFFER_SIZE];
				token += 2;
#ifdef _MSC_VER
				sscanf_s(token, "%s", namebuf, (unsigned)_countof(namebuf));
#else
				sscanf(token, "%s", namebuf);
#endif
				name = std::string(namebuf);

				continue;
			}

			if (token[0] == 't' && IS_SPACE(token[1])) {
				tag_t tag;

				char namebuf[4096];
				token += 2;
#ifdef _MSC_VER
				sscanf_s(token, "%s", namebuf, (unsigned)_countof(namebuf));
#else
				sscanf(token, "%s", namebuf);
#endif
				tag.name = std::string(namebuf);

				token += tag.name.size() + 1;

				tag_sizes ts = parseTagTriple(&token);

				tag.intValues.resize(static_cast<size_t>(ts.num_ints));

				for (size_t i = 0; i < static_cast<size_t>(ts.num_ints); ++i) {
					tag.intValues[i] = atoi(token);
					token += strcspn(token, "/ \t\r") + 1;
				}

				tag.floatValues.resize(static_cast<size_t>(ts.num_floats));
				for (size_t i = 0; i < static_cast<size_t>(ts.num_floats); ++i) {
					tag.floatValues[i] = parseFloat(&token);
					token += strcspn(token, "/ \t\r") + 1;
				}

				tag.stringValues.resize(static_cast<size_t>(ts.num_strings));
				for (size_t i = 0; i < static_cast<size_t>(ts.num_strings); ++i) {
					char stringValueBuffer[4096];

#ifdef _MSC_VER
					sscanf_s(token, "%s", stringValueBuffer,
						(unsigned)_countof(stringValueBuffer));
#else
					sscanf(token, "%s", stringValueBuffer);
#endif
					tag.stringValues[i] = stringValueBuffer;
					token += tag.stringValues[i].size() + 1;
				}

				tags.push_back(tag);
			}

			// Ignore unknown command.
		}

		bool ret = exportFaceGroupToShape(&shape, faceGroup, tags, material, name,
			triangulate);
		// exportFaceGroupToShape return false when `usemtl` is called in the last
		// line.
		// we also add `shape` to `shapes` when `shape.mesh` has already some
		// faces(indices)
		if (ret || shape.mesh.indices.size()) {
			shapes->push_back(shape);
		}
		faceGroup.clear();  // for safety

		if (err) {
			(*err) += errss.str();
		}

		attrib->vertices.swap(v);
		attrib->normals.swap(vn);
		attrib->texcoords.swap(vt);

		return true;
	}

	bool LoadObjWithCallback(std::istream &inStream, const callback_t &callback,
		void *user_data /*= NULL*/,
		MaterialReader *readMatFn /*= NULL*/,
		std::string *err /*= NULL*/) {
		std::stringstream errss;

		// material
		std::map<std::string, int> material_map;
		int material_id = -1;  // -1 = invalid

		std::vector<index_t> indices;
		std::vector<material_t> materials;
		std::vector<std::string> names;
		names.reserve(2);
		std::string name;
		std::vector<const char *> names_out;

		std::string linebuf;
		while (inStream.peek() != -1) {
			safeGetline(inStream, linebuf);

			// Trim newline '\r\n' or '\n'
			if (linebuf.size() > 0) {
				if (linebuf[linebuf.size() - 1] == '\n')
					linebuf.erase(linebuf.size() - 1);
			}
			if (linebuf.size() > 0) {
				if (linebuf[linebuf.size() - 1] == '\r')
					linebuf.erase(linebuf.size() - 1);
			}

			// Skip if empty line.
			if (linebuf.empty()) {
				continue;
			}

			// Skip leading space.
			const char *token = linebuf.c_str();
			token += strspn(token, " \t");

			assert(token);
			if (token[0] == '\0') continue;  // empty line

			if (token[0] == '#') continue;  // comment line

											// vertex
			if (token[0] == 'v' && IS_SPACE((token[1]))) {
				token += 2;
				float x, y, z, w;  // w is optional. default = 1.0
				parseV(&x, &y, &z, &w, &token);
				if (callback.vertex_cb) {
					callback.vertex_cb(user_data, x, y, z, w);
				}
				continue;
			}

			// normal
			if (token[0] == 'v' && token[1] == 'n' && IS_SPACE((token[2]))) {
				token += 3;
				float x, y, z;
				parseFloat3(&x, &y, &z, &token);
				if (callback.normal_cb) {
					callback.normal_cb(user_data, x, y, z);
				}
				continue;
			}

			// texcoord
			if (token[0] == 'v' && token[1] == 't' && IS_SPACE((token[2]))) {
				token += 3;
				float x, y, z;  // y and z are optional. default = 0.0
				parseFloat3(&x, &y, &z, &token);
				if (callback.texcoord_cb) {
					callback.texcoord_cb(user_data, x, y, z);
				}
				continue;
			}

			// face
			if (token[0] == 'f' && IS_SPACE((token[1]))) {
				token += 2;
				token += strspn(token, " \t");

				indices.clear();
				while (!IS_NEW_LINE(token[0])) {
					vertex_index vi = parseRawTriple(&token);

					index_t idx;
					idx.vertex_index = vi.v_idx;
					idx.normal_index = vi.vn_idx;
					idx.texcoord_index = vi.vt_idx;

					indices.push_back(idx);
					size_t n = strspn(token, " \t\r");
					token += n;
				}

				if (callback.index_cb && indices.size() > 0) {
					callback.index_cb(user_data, &indices.at(0),
						static_cast<int>(indices.size()));
				}

				continue;
			}

			// use mtl
			if ((0 == strncmp(token, "usemtl", 6)) && IS_SPACE((token[6]))) {
				char namebuf[TINYOBJ_SSCANF_BUFFER_SIZE];
				token += 7;
#ifdef _MSC_VER
				sscanf_s(token, "%s", namebuf,
					static_cast<unsigned int>(_countof(namebuf)));
#else
				sscanf(token, "%s", namebuf);
#endif

				int newMaterialId = -1;
				if (material_map.find(namebuf) != material_map.end()) {
					newMaterialId = material_map[namebuf];
				}
				else {
					// { error!! material not found }
				}

				if (newMaterialId != material_id) {
					material_id = newMaterialId;
				}

				if (callback.usemtl_cb) {
					callback.usemtl_cb(user_data, namebuf, material_id);
				}

				continue;
			}

			// load mtl
			if ((0 == strncmp(token, "mtllib", 6)) && IS_SPACE((token[6]))) {
				if (readMatFn) {
					char namebuf[TINYOBJ_SSCANF_BUFFER_SIZE];
					token += 7;
#ifdef _MSC_VER
					sscanf_s(token, "%s", namebuf, (unsigned)_countof(namebuf));
#else
					sscanf(token, "%s", namebuf);
#endif

					std::string err_mtl;
					materials.clear();
					bool ok = (*readMatFn)(namebuf, &materials, &material_map, &err_mtl);
					if (err) {
						(*err) += err_mtl;
					}

					if (!ok) {
						return false;
					}

					if (callback.mtllib_cb) {
						callback.mtllib_cb(user_data, &materials.at(0),
							static_cast<int>(materials.size()));
					}
				}

				continue;
			}

			// group name
			if (token[0] == 'g' && IS_SPACE((token[1]))) {
				names.clear();

				while (!IS_NEW_LINE(token[0])) {
					std::string str = parseString(&token);
					names.push_back(str);
					token += strspn(token, " \t\r");  // skip tag
				}

				assert(names.size() > 0);

				// names[0] must be 'g', so skip the 0th element.
				if (names.size() > 1) {
					name = names[1];
				}
				else {
					name.clear();
				}

				if (callback.group_cb) {
					if (names.size() > 1) {
						// create const char* array.
						names_out.resize(names.size() - 1);
						for (size_t j = 0; j < names_out.size(); j++) {
							names_out[j] = names[j + 1].c_str();
						}
						callback.group_cb(user_data, &names_out.at(0),
							static_cast<int>(names_out.size()));

					}
					else {
						callback.group_cb(user_data, NULL, 0);
					}
				}

				continue;
			}

			// object name
			if (token[0] == 'o' && IS_SPACE((token[1]))) {
				char namebuf[TINYOBJ_SSCANF_BUFFER_SIZE];
				token += 2;
#ifdef _MSC_VER
				sscanf_s(token, "%s", namebuf, (unsigned)_countof(namebuf));
#else
				sscanf(token, "%s", namebuf);
#endif
				std::string object_name = std::string(namebuf);

				if (callback.object_cb) {
					callback.object_cb(user_data, object_name.c_str());
				}

				continue;
			}

#if 0 
			if (token[0] == 't' && IS_SPACE(token[1])) {
				tag_t tag;

				char namebuf[4096];
				token += 2;
#ifdef _MSC_VER
				sscanf_s(token, "%s", namebuf, (unsigned)_countof(namebuf));
#else
				sscanf(token, "%s", namebuf);
#endif
				tag.name = std::string(namebuf);

				token += tag.name.size() + 1;

				tag_sizes ts = parseTagTriple(&token);

				tag.intValues.resize(static_cast<size_t>(ts.num_ints));

				for (size_t i = 0; i < static_cast<size_t>(ts.num_ints); ++i) {
					tag.intValues[i] = atoi(token);
					token += strcspn(token, "/ \t\r") + 1;
				}

				tag.floatValues.resize(static_cast<size_t>(ts.num_floats));
				for (size_t i = 0; i < static_cast<size_t>(ts.num_floats); ++i) {
					tag.floatValues[i] = parseFloat(&token);
					token += strcspn(token, "/ \t\r") + 1;
				}

				tag.stringValues.resize(static_cast<size_t>(ts.num_strings));
				for (size_t i = 0; i < static_cast<size_t>(ts.num_strings); ++i) {
					char stringValueBuffer[4096];

#ifdef _MSC_VER
					sscanf_s(token, "%s", stringValueBuffer,
						(unsigned)_countof(stringValueBuffer));
#else
					sscanf(token, "%s", stringValueBuffer);
#endif
					tag.stringValues[i] = stringValueBuffer;
					token += tag.stringValues[i].size() + 1;
				}

				tags.push_back(tag);
			}
#endif

			// Ignore unknown command.
		}

		if (err) {
			(*err) += errss.str();
		}

		return true;
	}
}  // namespace tinyobj

#endif

#endif  // TINY_OBJ_LOADER_H_